1. Technical Field of the Invention
The present invention generally relates to telecommunications. More particularly, and not by way of any limitation, the present invention is directed to a system and method for conducting diagnostic tests in a telecommunications node using a network card disposed therein.
2. Description of Related Art
The remote access market is undergoing a major metamorphosis. Three factors serve as catalysts for change. The first is the growing number of users, for example, small office/home office (SOHO) users, demanding high performance Internet and remote access for multimedia. Liberalized governmental activity with respect to telecommunications is another factor, which is fostering broader competition through deregulation in local area markets everywhere. The third and final factor is congestion in the Public Switched Telephone Network (PSTN), originally designed and developed for voice-only traffic.
There have been several important advances in telecommunications technology that enable high rates of throughput in carrier networks' backbone connections. For example, by implementing Asynchronous Transfer Mode (ATM) networking technology over a Synchronous Optical Network (SONET)/Synchronous Digital Hierarchy (SDH) physical layer, carrier networks can achieve data rates of up to several hundred megabits per second (Mbps). However, efforts to meet the bandwidth demand for remote access have been beset by the limitations of the existing twisted-pair copper cable infrastructure (i.e., access network) provided between a carrier's central office (CO) and a subscriber's remote site, typically referred to as the local loop. In the telecommunications art, these limitations are sometimes collectively described as the “last-mile” problem.
Current access network solutions that attempt to avoid the bottleneck created by the last-mile problem involve the use of fiber optic technology in the local loop also. As with the high-speed carrier networks, the fiber-based local loop infrastructure is typically architected using SONET as the physical layer technology. With recent developments in optical components and related opto-electronics, in addition to improvements in network design, broadband access is now becoming commonplace.
Moreover, in order to improve reliability of the access network, the equipment is necessarily deployed with redundancy, wherein critical components of an access node are provided in a duplex configuration. Additional safeguards are also typically provided in order to ensure that the access network operates with the so-called “five-nines” availability (i.e., 99.999% uptime).
In spite of these and other related advances, network reliability still remains an outstanding issue. Although redundant architecture ensures that there is duplicate hardware that can be pressed into action when a switchover is to be effectuated due to a failure in the node's active side, there is no certainty that the duplicate hardware in the node's standby side is error-free. It is possible that the standby hardware may exhibit what are known as “silent failures”—failures which show up on a network board only when it goes active, not when the board is first installed. Although the occurrence of such failures may be somewhat rare, the effect is nevertheless devastating, resulting not only in the loss of traffic, but also in the diminution of the network operator's prestige and the trust it places in the equipment manufacturer.
One approach to address this problem is to utilize whatever diagnostic capability that the existing software operable to control the network card may have, in order to run appropriate tests on the card to ensure that there are no failures. A significant disadvantage in this approach is that the existing software's diagnostic capabilities may not be suitable for testing the board-level or backplane-level hardware, where test patterns are typically required to traverse only several inches or so. For example, where SONET-capable equipment is deployed, the SONET software running on the network cards is operable to detect failures in signals that traverse several miles (i.e., long-delay loops). Accordingly, such test software is necessarily equipped with broader tolerances, which renders the diagnostic methodology rather insensitive for testing the much shorter distances (i.e., short-delay loops) required for the board-level or backplane-level components.
Another solution involves modifying the existing software to include the capability to test hardware disposed on short-delay test loops. However, this approach results in incorporating extensive changes in legacy software, which can ultimately lead to the instability of the software itself. Furthermore, the type and number of tests that can be performed without creating too many changes is limited as a consequence.